Don's got it - IR is what you feel as heat. Heat rays. metal might
reflect it unless it were etched and ready to absorb. I'd try
the black paint and the cardboard idea is spot on. If it doesn't work
then apply another material. A rug would be good, but grabs dirt.
Martin

On 7/14/2015 7:19 PM, wrote:
On Tuesday, July 14, 2015 at 7:51:32 PM UTC-4, Bob Engelhardt wrote:
On 7/14/2015 7:12 PM, wrote:
... I thought about maybe
taking the thing apart and putting a mirror inside that would make the
sensor see at an angle so that it wouldn't detect the underside of the
countertop but then it might open when someone walks past. ...

How about putting the mirror under the counter top?


I would try some aluminum foil taped under the counter top.

If you really need an adsorber, you could try some black paint. I would try black paint on cardboard before painting the underside of the counter.

How about a make and model? The manufacturer might have some info that would help figure out a solution.

Dan